I was looking at the plane 2 characters in the March 15, 2001 version of
the unihan.txt file, and found five that did not have an IRG source:
U+20957, U+221EC, U+22FDD, U+24FB9, and U+2A13A. (The last one, U+2A13A,
however, has kIRGHanyuDaZidian and kIRGKangXi information showing that it
can be found in those dictionaries. Still, shouldn't there be an IRG
source for it?) Where are the first four from?